The desire for resilient powder coatings is becoming increasingly popular. Today, there are well known basic powder chemistries that have been utilized over the past several decades that meet standard durability requirements. However, most powder chemistries available in the current industry are not equipped with the appropriate chemical makeup for extreme situations or environments. As this form of ultra-durable powder coating becomes more prevalent, innovations of the chemical makeup of typical powder coating chemistries is in high demand.
Today, there are several well-known chemical makeups known in the industry that are defined as durable powder coatings. Examples of known durable powder chemistries include: polyester, polyester/isocyanate, acrylic and fluoropolymer powder coatings. More than 60 percent of the market utilizes polyester-based coatings, which are equipped to withhold a measurable amount of standard outdoor environments such as corrosion and ultra-violet light exposure. Depending on the specifications these powder coatings are available in a wide gloss range from high-gloss to dull-matte finish. Furthermore it is known that Fluoropolymer based powder coatings have a very high chemical and UV resistance. But up to now no suitable solution is known to make a low gloss powder coating based on that kind of materials, especially in a gloss range below 10 and furthermore in particular below 5.
U.S. Pat. No. 9,206,320 relates to a matte-appearance chemical-agent-resistant powder coating composition comprising a resin component, a polyisocyanate-containing uretdione cross-linking agent, a catalyst, and a flattening agent. The resin component may comprise a hydroxyl-containing resin and a hydroxyl-containing halogenated copolymer resin. Catalyzed cross-linking of the uretdione isocyanate groups and resins of the resin component during curing yields a finished-form film with low levels of gloss and sheen and chemical-agent resistance.
EP 2635646 describes matte textured powder monocoat coating compositions comprising a polyester resin, a UV light stabilizer, a matting agent, and a texturing additive, wherein the cured powder coating composition transmits less than about 0.1% of UV light at 290 nm and less than about 0.5% of UV light at 400 nm.
U.S. Pat. No. 4,122,055 relates to an aqueous dispersion type thermosetting coating composition consisting essentially of a homogeneous mixture of an aqueous medium, a powder of a thermosetting resin having an acid value of 5 to 30, a carboxyl group-containing organic polymeric thickener, and an organic amine and/or an alkali metal hydroxide.
GB 1523903 discloses a coating composition which comprises a binder comprising a) the reaction product of an hardenable polyester and a partially blocked polyisocyanate and b) an amount of up to 38.5% by weight of an epoxy resin.
US 2010/0189905 relates to a method of forming a multilayer coating film of excellent appearance by the so-called 3-coat-1-bake system, comprising successively applying onto a coating object, a water-based intermediate paint, water-based base paint and a clear paint; and then simultaneously heat-curing the resulting 3-layered coating film.
WO 2015/005434 provides a coating material composition containing (A) a hydroxyl-containing acrylic resin, (B) a hydroxyl-containing polyester resin, (C) a color pigment and/or a photoluminescent pigment, and (D) a polyisocyanate compound, wherein the hydroxyl-containing polyester resin (B) has a hydroxyl value of 20-250 mg KOH/g and is obtained by reacting a polybasic acid and a polyhydric alcohol including a cyclic polyol compound (b 1) having a nurate structure, and the solid content of the hydroxyl-containing polyester resin (B) is 5-60% by mass based on the total resin solids of the (A) and (B) components.
U.S. Pat. No. 6,825,258 describes a powder coating additive composition containing (a) a non-crosslinked product made by the reaction of an organic alcohol and a carboxylic acid or a reactive equivalent of the carboxylic acid; the product containing at least one ester functionality and at least one hydrocarbyl group of about 10 to about 100 carbon atoms; and (b) a fluoropolymer. The cured coatings exhibit lower coefficient of friction and substantial gloss retention.
US 2012/0270055 relates to a process for making highly mechanical and chemical resistant ceramic substrates, comprising coating said substrates with a base coat layer of a thermosetting or radiation curable powder coating composition, curing the applied powder coating composition, and applying a further layer of a liquid coating composition and curing the composition by exposure to heat.
U.S. Pat. No. 7,034,075 is directed to a low gloss powder coating composition comprising a first component (a) comprising a mixture of (i) at least one glycidyl group-containing acrylic resin having epoxide equivalent weight of from about 250 to about 1500 and glass transition temperature of from about 30° C. to about 80° C.; and (ii) a curing agent, and a second component (b) comprising at least one carboxyl-group containing material having acid number of from about 10 to about 300 and is not substantially compatible with the first component (a). The two components are dry-blended to obtain the powder coating composition.
U.S. Pat. No. 7,816,421 describes a radiation curable powder coating composition for preparing low gloss coatings, comprises as a binder a mixture of 30 to 90 weight % of one or more (meth)acryloyl group containing amorphous polyester resins having an unsaturated equivalent weight of more than 700 g/double bond and 10 to 70 weight % of one or more (meth)acryloyl group containing acrylic copolymers having an unsaturated equivalent weight of less than 700 g/double bond.
U.S. Pat. No. 5,104,955 relates to acrylic-modified hydroxy-functional polyester reactive diluents which may be copolymerized with one or more acrylic monomers, and blended with a variety of thermosetting or thermoplastic film-forming polymers. These blends of the film-forming polymers and the hydroxy-functional polyester diluents can be crosslinked with conventional crosslinking agents such as isocyanates and used in the formulation of low VOC paint compositions particularly useful as automotive topcoats.
EP 1316593 discloses a coating powder composition comprising a mixture of a first film-forming system comprising a GMA resin, a curing agent, and a catalyst; and a second film-forming system comprising a carboxyl terminated polyester, an acrylic resin, and a catalyst.
U.S. Pat. No. 8,969,577 relates to curable compositions comprising a thermolatent amidine base and an organic material which is polymerizable or crosslinkable with a basic or nucleophilic catalyst. In particular, the document relates to curable coating compositions, especially powder coating compositions, and curable adhesive compositions, as well as to the use a thermolatent amidine base as a curing catalyst for thermally induced base-catalyzed polymerization or crosslinking reactions.
U.S. Pat. No. 9,012,556 describes a powder coating composition consisting essentially of (a) a first hydroxyl functional acrylic powder resin having a hydroxyl value of at least about 180; (b) a second hydroxyl functional acrylic powder resin having a hydroxyl value less than about 45; (c) a crosslinker reactive with the hydroxyl functional acrylic resins; and (d) wollastonite; wherein the weight ratio of the first acrylic powder resin to the second acrylic powder resin is greater than 1.0.
It is known that powder coatings based on crosslinkable fluoropolymers or fluorocopolymers can achieve outstanding weather and chemical resistance. However, the need of such a powder coating with low gloss levels (below 30) could not be solved sufficiently. The present invention offers a solution to create a fluoropolymers or fluorocopolymers based powder coating with a gloss level below 30, even down to a gloss level of below 5. With this low gloss level the present invention allows the use of this powder coating even for military applications.